JP2708196B2 - Multiple subsampling signal adapter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a multiplex sub-sampling transmission / reception system (for example, a multi-sampling transmission / reception system for compressing and transmitting a high-definition television signal after demodulating the band).
The present invention relates to a multi-subsampling signal adapter device which is applied to a MUSE decoder and is effective when a MUSE decoder is connected to a digital recording / reproducing device.

(Prior Art) The MUSE system has been developed as a high-definition television transmission system. This method is disclosed, for example, in Japanese Patent Application No. 60-106132, NH
It is also described in literature such as K Technology Research vol.39, NO2. MUS
In the E system, a high-definition television signal is band-compressed to 8.1 MHz as a multiplexed sub-sampling signal and transmitted using, for example, satellite broadcasting.To reproduce the signal, it is received by a satellite broadcasting receiver and demodulated. After that, playback is performed using a so-called MUSE decoder.

FIG. 7 shows a satellite broadcast receiving system for receiving a television signal according to the MUSE system. The satellite broadcast wave received by the antenna 1 is received and demodulated by a satellite broadcast tuner (hereinafter referred to as a BS tuner) 2 and supplied to a selector 3. The selector 3 can guide the received signal to the MUSE decoder 4 and also to a high-vision device (for example, a magnetic recording / reproducing device) 6. The high-definition television signal reproduced by the MUSE decoder 4 is introduced to a monitor 5 and displayed.

In the magnetic recording / reproducing apparatus 6, a digital signal processing circuit has recently been developed along with the development of digital technology. The adapter between the magnetic recording / reproducing apparatus and the MUSE system has a configuration as shown in FIG. Can be considered.

That is, the MUSE baseband signal demodulated by the BS tuner is supplied to the analog / digital converter 11 via the input terminal 10.
Is input to The output of this analog-to-digital converter 11
10-bit data is supplied to the digital output terminal 12 and one input section a of the mode changeover switch 13. The reason why the output of the analog-to-digital converter 11 is set to 10 bits is that a resolution of about 10 bits is required when performing non-linear level expansion and de-emphasis processing to perform transmission path compensation. The other input b of the switch 13 is connected to the digital input terminal.
The digital output terminal 12 and the digital input terminal 14 are respectively connected to an input terminal and an output terminal of a magnetic recording / reproducing device as a high-vision device. The output signal selected by the mode switch 13 is supplied to a non-linear level extending circuit 15 to be extended, and then supplied to a de-emphasis circuit 16. This is because level compression and pre-emphasis are performed on the transmission side in order to reduce signal distortion in the transmission path.

Further, the output of the de-emphasis circuit 16 is input to a transmission inverse gamma circuit 17, output as 8-bit data, and supplied to a video signal processing unit 18 as a decoder.

When reproducing the MUSE signal from the magnetic recording / reproducing apparatus, the switch 13 is switched to the terminal b. Note that the output of the mode switch 13 is also supplied to a control signal reproducing unit 19, a synchronization detecting circuit 20, and an audio processing unit 22. The synchronization signal detected by the synchronization detection circuit 20 is supplied to a timing generator 21 and used to obtain a system clock and various timing signals.

(Problem to be Solved by the Invention) With the adapter shown in FIG. 6, a 10-bit signal at the output section of the analog-to-digital converter 11 can be recorded by a magnetic recording / reproducing device, The configuration is such that 10-bit data is reproduced and input to the switch 13. With such an adapter, there is a problem that the circuit configuration of the digital recording / reproducing circuit becomes complicated because the data handled by the magnetic recording / reproducing device is 10 bits. In addition, there is a problem that a memory used in the digital recording / reproducing circuit requires a large capacity and is expensive.

Therefore, the present invention provides an 8-bit (25-bit)
Focusing on the fact that 6-gradation) data is sufficient, a multiplexed sub-sampling signal adapter that supplies low-bit data to digital recording / reproducing equipment such as magnetic recording / reproducing devices to reduce the burden It is intended to provide a device.

[Means for Solving the Problems] In order to solve the above problems, a multiplex sub-sampling signal adapter device according to the present invention is an analog device to which a multiplex sub-sampling signal received and demodulated by a tuner is input. An input terminal; an analog-to-digital converter that converts a multiplexed sub-sampling signal from the analog input terminal into a 10-bit digital signal; a digital input terminal to which an external 8-bit digital signal is input; Switch means for selecting and outputting one of a digital signal from a switch and a digital signal from the digital input terminal by a mode switching signal; and a non-linear level to which an output signal of the first switch means is inputted. An expansion circuit and a de-encoder to which the output of the nonlinear level expansion circuit is input. First and second transmission path compensating means for outputting 8-bit data, the first switching means comprising an analog-to-digital converter, comprising a transmission inverse gamma circuit to which an output of the de-emphasis circuit is inputted. When the digital signal from the first transmission path compensating means is selected, and when the first switching means selects the digital signal from the digital input terminal, the output of the first switching means is selected. Second to select the signal
Switch means; a multiplexed sub-sampling signal decoder to which a signal selected by the second switch means is inputted; and the second switch means when the first switch means selects a digital signal from the analog-to-digital converter. Selecting the output signal of the transmission path compensating means, and selecting the output signal of the first switching means when the first switching means selects the digital signal from the digital input terminal.
And a digital output terminal for outputting the signal selected by the third switch to the outside.

(Operation) With such a configuration, in the present invention, the digital recording / reproducing device connected to the digital output terminal handles low-bit (8-bit) signals, so that the circuit scale can be reduced. The transmission path compensating means including the non-linear level expansion circuit, the de-emphasis circuit and the transmission inverse gamma circuit is provided separately for both the input to the multiplexed sub-sampling signal decoder and the output to the digital output terminal. The transmission path compensation can be optimized for each, and when the first switch selects a digital signal from the digital input terminal, the third switch outputs the digital signal as it is to the digital output terminal. At this time, the digital signal output from the digital output terminal can be used for dubbing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The first is an embodiment of the present invention. Input terminal 30
An analog MUSE signal received and demodulated by the BS tuner is supplied. The analog MUSE signal is subjected to a clamp process by the clamp circuit 32 via the reduction filter 31, and then input to the analog-to-digital converter 33. In the analog-to-digital converter 33, 10 bits per sample are quantized, and the output is supplied to the terminal A of the mode switch SW1. The switch SW1 selects either the terminal A or the terminal B, and outputs the output of the switch SW1 to the non-linear level extending circuit 35.
Enter 51. A digital input terminal 55 is connected to the terminal B of the switch SW1, and an output terminal of an external digital recording / reproducing device is connected here.

The output of the non-linear level expansion circuit 35 can be input to the de-emphasis circuit 36 via the switch SW2, and the output of the de-emphasis circuit 36 can be input to the transmission inverse gamma circuit 37 via the switch SW3. The output of the transmission inverse gamma circuit 37 is connected to the MUS via the switch SW4.
It can be input to the E video signal processing unit 38.

FIG. 2 shows an example of a non-linear level extension characteristic, and FIG. 3 shows an example of a de-emphasis characteristic. FIG. 4 is an example of a transmission inverse gamma characteristic for a luminance signal. Since the transmission inverse gamma characteristic for the chrominance signal is different from that for the luminance signal, gamma correction suitable for the luminance signal and the chrominance signal is performed at different timings.

Here, the switches SW2, SW3, and SW4 are all connected to the input terminal B.
When the side is selected, the output of switch SW1
It can be input to the video signal processing unit 38. When the switches SW2, SW3, and SW4 all select the input terminal A side, the non-linear level expansion circuit 35 and the de-emphasis circuit
36, a series circuit of a transmission inverse gamma circuit 37 and a MUSE video signal processing unit 38 is formed.

The circuit configuration including the non-linear level expansion circuit 51, the switch SW12, the de-emphasis circuit 52, the switch SW13, the transmission inverse gamma circuit 53, and the switch SW14 has the same configuration as the configuration from the non-linear level expansion circuit 35 to the switch SW4.
However, the output of the switch SW14 is connected to the digital output terminal 54.

The output of the switch SW1 is also supplied to a timing signal generating means for obtaining system synchronization and a control signal reproducing means for controlling the system. The control signal reproducing unit 39 reproduces various control signals included in the MUSE signal. For example, when decoding is performed with image motion information as a control signal, the field position is corrected and used as control information for adjusting to the next field. On the other hand, the timing signal generating means
The synchronization signal detected at the position of the synchronization detection circuit 4 is supplied to the timing generator 42 and used for obtaining various timing signals. Further, a loop formed by the phase comparator 43, the switch SW5, the voltage control oscillator 45, and the timing generator 42 forms a phase locked loop, and synchronizes the phase of the internal clock with the sampling clock of the received signal. Here, when the switch SW5 selects the output of the phase comparator 44 and supplies it to the voltage controlled oscillator 45, a phase locked loop is formed by the voltage controlled oscillator 45, the timing generator 42, and the phase comparator 44, and the internal clock is output. Is synchronized with the sampling clock of external data supplied from the digital input terminal 55.

One embodiment of the present invention is configured as described above. To play back analog MUSE signal video, switch SW1
SW5 are connected to the respective terminal A sides. As a result, the MUSE video signal processing unit 38 includes a nonlinear level expansion circuit.
35, a signal subjected to transmission path compensation through a de-emphasis circuit 36 and a transmission inverse gamma circuit 37 is input. On the other hand, the signal that has passed through the non-linear level expansion circuit 51, the de-emphasis circuit 52, and the transmission inverse gamma circuit 53 is output to the digital output terminal 54 as an 8-bit MUSE signal. The internal clock obtained by the timing generator 42 is also guided to the digital output terminal 54. Digital MUSE derived here
The signal is supplied to a digital recording / reproducing device and recorded on a recording medium (a disk or a magnetic tape or the like).

On the other hand, when reproducing the digital MUSE signal from the digital recording / reproducing apparatus, the digital input terminal 55 is supplied with an 8-bit digital MUSE signal and a reproduction clock. At this time, the switches SW1 to SW5 are respectively switched and connected to the terminal B side. Therefore, the internal clock in the adapter is phase-synchronized with the reproduced clock from the digital recording / reproducing device, and the digital MUSE signal introduced to the switch SW1 is supplied to the MUSE signal processing unit 38 via the switches SW2, SW3, and SW4.
Is input to This allows digital recording and playback devices to
The MUSE signal is reproduced. On the other hand, switches SW12, SW13, SW
Digital MUSE derived to digital output terminal in 14 paths
The signal is used, for example, for dubbing.

FIG. 5 shows another embodiment of the present invention. In the above embodiment, the transmission path compensating section and the switch array are composed of two sets. In the embodiment of FIG. 5, however, the extraction position of the digital output terminal 54 is devised to make one set. That is, in this embodiment, the digital output terminal 54 is connected to the input unit of the MUSE video signal processing unit 38. The non-linear level expansion circuit 51, the de-emphasis circuit 52, the transmission inverse gamma circuit 53, and the switches SW12, SW13, and SW14 in the previous embodiment are omitted. Even with such a configuration, the same effect as in the previous embodiment can be obtained. The 8-bit data introduced from the digital input terminal 55 and the 8-bit data output from the transmission inverse gamma circuit 37 are adjusted so that the weights are the same.

[Effects of the Invention] According to the above-described present invention, attention is paid to the fact that 8-bit (256 gradation) data is sufficient to obtain image reproduction, and a low level is required for digital recording / reproducing equipment such as a magnetic recording / reproducing apparatus. The load can be reduced by supplying bit data. Also, the recording efficiency for digital recording media is improved as compared with 10-bit recording.

Further, the transmission path compensating means including the non-linear level expansion circuit, the de-emphasis circuit and the transmission inverse gamma circuit is provided separately for both the input to the multiplexed sub-sampling signal decoder and the output to the digital output terminal. The transmission path compensation can be optimized for each, and when the first switch selects a digital signal from the digital input terminal, the third switch outputs the digital signal as it is to the digital output terminal. At this time, the digital signal output from the digital output terminal can be used for dubbing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing an example of a non-linear level extension characteristic, FIG. 3 is a diagram showing an example of a de-emphasis characteristic, and FIG. FIG. 5 is a block diagram showing another embodiment of the present invention, FIG. 6 is a diagram showing a conventional example of an adapter device, and FIG. 7 is an explanatory diagram showing a satellite broadcast receiving system. 31 ... Low-pass filter, 32 ... Clamp circuit, 33 ... Analog-to-digital converter, 35,51 ... Non-linear level expansion circuit, 36,52 ... De-emphasis circuit, 37,53 ... Transmission inverse gamma circuit, 38 MUSE video signal processing unit, SW1 to SW3, SW1
2 to SW14 ... Switch, 54 ... Digital output terminal, 55 ...
... Digital input terminal.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Shinkai 8-8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliances Research Laboratory, Toshiba Yokohama Office (72) Inventor Yu Sakurai Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 8 Toshiba Corporation Yokohama Office, Home Appliance Research Laboratory (56) References JP-A-63-67984 (JP, A)

Claims (1)

(57) [Claims] An analog input terminal to which a multiplexed sub-sampling signal received and demodulated by a tuner is inputted, an analog-to-digital converter for converting the multiplexed sub-sampling signal from the analog input terminal into a 10-bit digital signal, A digital input terminal to which an 8-bit digital signal from the outside is input, and one of a digital signal from the analog-to-digital converter and a digital signal from the digital input terminal selected and output by a mode switching signal. 1 switch means, a non-linear level extending circuit to which an output signal of the first switch means is inputted, a de-emphasis circuit to which an output of the non-linear level extending circuit is inputted, and an output of the de-emphasis circuit to be inputted. A transmission inverse gamma circuit for outputting 8-bit data And second transmission path compensating means; and selecting the output signal of the first transmission path compensating means when the first switching means selects a digital signal from the analog-to-digital converter; Second switch means for selecting an output signal of the first switch means when the means selects a digital signal from the digital input terminal; and a multiplex sub-input to which a signal selected by the second switch means is inputted. A sampling signal decoder, selecting an output signal of the second transmission path compensating means when the first switching means selects a digital signal from the analog-to-digital converter; A third switch for selecting an output signal of the first switch when a digital signal from a terminal is selected; Multiple sub-sampling the signal adapter device, characterized by comprising a digital output terminal for outputting a signal selected by the switch means to the outside.